全文获取类型
| 收费全文 | 183篇 |
| 免费 | 27篇 |
| 国内免费 | 8篇 |
专业分类
| 电工技术 | 63篇 |
| 综合类 | 11篇 |
| 化学工业 | 54篇 |
| 金属工艺 | 1篇 |
| 机械仪表 | 2篇 |
| 建筑科学 | 8篇 |
| 矿业工程 | 1篇 |
| 能源动力 | 9篇 |
| 轻工业 | 29篇 |
| 水利工程 | 3篇 |
| 石油天然气 | 1篇 |
| 武器工业 | 1篇 |
| 无线电 | 12篇 |
| 一般工业技术 | 10篇 |
| 冶金工业 | 1篇 |
| 原子能技术 | 3篇 |
| 自动化技术 | 9篇 |
出版年
| 2024年 | 1篇 |
| 2023年 | 8篇 |
| 2022年 | 7篇 |
| 2021年 | 10篇 |
| 2020年 | 7篇 |
| 2019年 | 4篇 |
| 2018年 | 6篇 |
| 2017年 | 7篇 |
| 2016年 | 8篇 |
| 2015年 | 10篇 |
| 2014年 | 20篇 |
| 2013年 | 25篇 |
| 2012年 | 13篇 |
| 2011年 | 22篇 |
| 2010年 | 12篇 |
| 2009年 | 14篇 |
| 2008年 | 9篇 |
| 2007年 | 8篇 |
| 2006年 | 4篇 |
| 2005年 | 10篇 |
| 2004年 | 4篇 |
| 2003年 | 1篇 |
| 2001年 | 4篇 |
| 2000年 | 1篇 |
| 1999年 | 2篇 |
| 1997年 | 1篇 |
排序方式： 共有218条查询结果，搜索用时 15 毫秒
81.
针对电网EMS系统中各个高级应用模块在调用BPA暂态计算程序时出现的接口程序继承性差、接口程序调用效率低下的不足,提出了一种快速有效调用BPA暂态计算程序的接口设计方法。通过设定统一的BPA暂态计算程序接口调用模式和文件交互标准,解决了BPA暂态计算程序接口继承性差的问题。同时,根据EMS高级应用调用BPA暂态计算程序的特点,设计了一种快速调用BPA暂态计算程序的接口设计方法,实现了BPA暂态计算程序的快速调用。利用精细规则自动发现系统在广东省电网调用BPA暂态计算程序的算例测试表明:该接口程序能够提供继承性强的BPA暂态计算程序的接口程序,并且可以实现BPA暂态计算程序的快速调用。 相似文献
82.
应用证据理论的一个关键问题是生成基本概率指派(BPA),目前如何生成BPA仍然是一个有待解决的问题.本文提出一种基于区间数的BPA生成方法,首先建立样本属性的区间数模型,然后用区间数的距离表示样本属性之间的差异性,在此基础上提出了一种相似度,最后对相似度进行归一化得到BPA.通过鸢尾花数据集(Iris Data Set)的分类实验验证了该方法的有效性,结论表明整体识别率为96％.本文方法简单实用,数据样本较少情况下也能有效确定BPA. 相似文献
83.
利用电荷平衡原理,在功能化石墨烯改性环氧树脂的过程中,设计了一种通过添加少量电解质溶液破坏功能化石墨烯体系的电荷平衡,以加速功能化氧化石墨烯的沉降速率,从而在低速离心条件下快速去除双酚A(BPA)功能化石墨烯(BPA-GO)中存在的过量BPA的方法。同时,采用传统的透析法与之进行对比实验,选用红外光谱仪、紫外-可见分光光度计对两种方法的纯化效果进行了分析,且采用离心分离法探讨了转速对所提方法分离效果的影响。结果表明,所提出的纯化方法对样品的结构没有产生影响,且所提方法相比于传统的透析法,不仅纯化效率较高、效果较好、对设备要求较低,而且具有适用于工业化生产的优点。 相似文献
84.
双酚A(BPA)的内分泌干扰作用以及对人体产生的不良影响,使双酚S(BPS)作为替代品在食品包装材料中应用更加广泛。BPS在大规模应用之前,并没有对其安全性进行充分研究。本文以3T3-L1前脂肪细胞为体外模型,探究BPS对3T3-L1前细胞分化的影响及作用途径,评价BPS安全性的同时,也为肥胖等慢性代谢疾病的预防提供参考。研究结果表明:BPS能促进3T3-L1前脂肪细胞生长,当浓度超过400μmol/L时,才能显著抑制细胞的增殖;BPS能显著诱导分化的3T3-L1细胞内脂质的积累,并呈现非剂量依赖关系;与模型组相比,BPA上调PPARγ、C/EBR和aP2基因的表达,而BPS只作用PPARγ基因的过表达,BPS和BPA都能使GLUT4基因的表达显著下降(p0.01)。总之BPS和BPA作用脂肪细胞分化的途径不完全一样,可能是在多种转录因子的共同作用下完成的。 相似文献
85.
采用一系列不同截留分子量的超滤膜将提取的天然有机物(NOM)滤分为6种组分(NOM10K、NOM5K-10K、NOM3K-5K、NOM1K-3K、NOM500-1K、NOM500)组分,并研究了这6种NOM组分对臭氧(O3)氧化降解水中两种典型微污染有机物(双酚A和硝基苯)的影响.结果表明:对于与O3反应活性较高的有机物双酚A(BPA),NOM各组分的引入使得O3去除BPA效能有所下降;对于与O3反应活性较低的有机物硝基苯(NB),高分子量范围的NOM组分(NOM10K、NOM5K-10K、NOM3K-5K、NOM1K-3K)的存在能强化O3的自由基链式分解反应,从而促进O3对硝基苯的去除.低质量浓度的NOM对O3氧化降解水中有机物的影响与NOM的特性(所含的官能团的类型和数量)以及目标有机物与O3的反应活性有关. 相似文献
86.
Jun Yang Shulin Hu Anqi Liao Yetian Weng Shuli Liang Ying Lin 《Food Science & Nutrition》2022,10(6):1841-1853
Current chemical analysis approaches for contaminants have failed to reveal their biotoxicity. Moreover, conventional bioassays are time consuming and exhibit poor repeatability. In this study, we performed the acute toxicity detection of various contaminants (chromium (Cr), cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), tin (Sn), nickel (Ni), and bisphenol A (BPA)) with four bioluminescent bacteria (Vibrio qinghaiensis Q67, V. fischeri, Photobacterium phosphoreum T3, and P. phosphoreum 502) using a rapid, flexible, and low-cost bioassay. We found that the temperature affected the bacterial luminescence, and freeze-dried cells exhibited sensitive toxic responses to contaminants. Indeed, the optimized protectants containing 12% (w/v) trehalose, 4% sucrose, and 2% sorbitol displayed better luminescence and toxic sensitivity. Furthermore, freeze-dried powders of these strains were prepared and subjected to acute toxicity detection. The results showed that all contaminants exhibited acute toxicity toward Q67, but the other strains did not show obvious response to nickel and tin. The relative half-maximal effective concentration (EC50) values of BPA, Cr, Cd, Pb, As, Hg, Ni, and Sn to Q67 were 0.674, 1.313, 11.137, 5.921, 4.674, 0.911, 5.941, and 54.077 mg/L, respectively. In addition, the EC50 values of contaminants toward different strains were suggested to be statistically significant. Freeze-dried Q67 exhibited toxic responses to more contaminants than the other bioluminescent strains; therefore, Q67 was selected to be more suitable than the other strains for single and mixture toxicity detection tests. Compared with other strains, Q67 was more appropriate for the rapid screening of the mixture toxicity of contaminants in samples as a nonspecific screening sensor before the use of standard analysis approaches. 相似文献
87.
Liujun Yang Junwei Yuan Guan Wang Qiang Cao Cheng Zhang Miaomiao Li Junxia Shao Yan Xu Hua Li Jianmei Lu 《Advanced functional materials》2023,33(28):2300954
This study proposes the construction of porous nanomaterial (HOFs@Fe3+) which anchors non-noble metal ions Fe3+ onto nanoscale rod-like hydrogen-bonded organic frameworks (HOFs) by electrostatic and coordination interactions. The high specific surface area and the abundance of hydrogen-bond adsorption active sites in pore structure of HOFs@Fe3+ facilitate strong interactions with the double OH in bisphenol A (BPA), resulting in the highest saturation adsorption of BPA that has been reported so far (452 mg g-1). In addition, the ordered conjugate stacking framework structure and hydrogen bond of HOFs@Fe3+ and the variable valence properties of Fe3+ create new pathways for efficient separation of photogenerated carriers. The results show that HOFs@Fe3+ can completely adsorb and photodegrade 50 ppm BPA within 20 min, owing to the abundant hydrogen bond that acts both as adsorption sites to accelerate the mass transfer process and as catalytic sites to ensure adsorption and photodegradation can be matched synergistically. Meanwhile, the efficiency of photocatalytic H2 production by HOFs@Fe3+ reaches 21.55 mmol g-1 h-1 with non-noble metal Fe3+ as co-catalyst. This tri-functional material with high adsorption capacity, high photodegradation efficiency, and high photocatalytic H2 production activity can be successfully used to solve the long-standing conflict between environment and energy. 相似文献
88.
Pin-Jing He Zhong Zheng Hua Zhang Li-Ming Shao Qiong-Yao Tang 《The Science of the total environment》2009,407(17):4928-4933
An increasing attention has been paid to the trace endocrine disrupting compounds (EDCs) in landfill leachate. In this paper, the removal of EDCs including phthalic acid esters (PAEs) and bisphenol A (BPA) from the fresh and mature landfill leachate by Fenton treatment was studied. More than 40% of PAEs and about 62% of BPA were removed from the raw mature leachate while only 20% of PAEs and 37% of BPA in the raw fresh leachate were reduced, respectively. After the fresh and mature leachates were spiked with PAEs to 1.5 mg L− 1 and BPA to 0.08 mg L− 1, the removal efficiencies of BPA and PAEs increased to more than 88%. The results indicated that the removing efficiencies of the EDCs in the leachate had a relationship with their concentrations, and that the trace levels of EDCs in leachate challenged the treatment capacity of the Fenton process. Most of the EDCs in the enriched leachate were removed by oxidation, which had no clear correlation with the hydrophobicity of the EDCs. The flocculation played an important role in the removal of di-(2-ethylhexyl) phthalate that could not be completely oxidized in the Fenton process, in that the EDCs with high n-octanol/water partition coefficient inclined to precipitate after the Fenton process. The dissolved organic matter (DOM) in the fresh leachate inhibited the EDCs removal more than the DOM in the mature leachate did. Both the composition of the leachate DOM and the characteristics of the EDCs determined the removing efficiencies of the EDCs in the Fenton process. 相似文献
89.
机电暂态仿真工具BPA在我国得到了广泛应用,对同一网络通过PSCAD／EMTDC仿真时,通常根据BPA模型数据文件的网络拓扑结构及元件参数在PSCAD／EMTDC中手动重新建模,该方式费时、费力且容易出错。为此,基于图论的关联矩阵、深度优先搜索等理论,先根据BPA网络数据重新生成网络树,计算网络节点坐标,确定网络元件模型结构及参数,完成BPA的电网系统数据向PSCAD／EMTDC的模型转换,自动转换后的系统网络具有与原系统相同的网络拓扑结构及等效的元件参数,提高了在PSCAD／EMTDC中进行电网建模的效率及精度。 相似文献
90.